This project seeks to investigate, characterize, understand and define the possible involvement of the benzodiazepine-GABA receptor-ionophore complex in alcohol actions and in its tolerance and withdrawal. The effects of in vitro and in vivo (acute and chronic) ethanol administration on the binding characteristics of benzodiazepines, GABA agonists and picrotoxinin in C57 mice will be investigated. The in vitro studies will involve investigating the interaction of alcohols (with increasing chain lengths) on the binding of ligands to membranes, crude lubrol fraction, 61,000 dalton fraction (benzodiazepine receptor) and 185,000 dalton fraction (picrotoxin receptor). For in vivo studies, the effects of ethanol treatment on GABA levels and the classes of binding sites, affinities and binding capacities will be compared in pair-fed controls acute, chronic, withdrawing and recovered animals. The effect of in vivo ethanol will be investigated in whole C57 mice brains and discrete brain regions. We will also investigate the lipid dependence of alcohol interaction with the binding sites in vitro. The radioligands to be used in this study bind to three distinct but interacting components of the benzodiazepine-GABA receptor-ionophore complex, namely (a) GABA receptors, (b) benzodiazepine binding sites and (c) picrotoxin (DHP) sites. The binding data will be compared and correlated with blood alcohol levels and behavioral indicators. The in vitro assays selected for this study will help us pinpoint the site at the GABA postsynaptic apparatus which may be involved in alcohol action, in its tolerance and withdrawal. A clearer understanding of the effects of alcohol on the benzodiazepine-GABA system at the molecular level is fundamental to our understanding of the basis of alcohol action, its tolerance and withdrawal and in the development of a rational central nervous system therapy for alcoholism. Molecular interactions of alcohol with the benzodiazepine binding sites may also help us understand the most abused drug combination, i.e. alcohol and Valium (diazepam).